The in vitro and in vivo degradation behavior of poly (trimethylene carbonate- co -ε-caprolactone) implants

The degradation behavior of P(TMC-co-CL) in different compositions was investigated via subcutaneous implantation in vivo. To clarify the role of enzymes in the degradation behavior of the copolymers, hydrolytic and enzymatic degradation were also performed. The mass loss, changes in molecular weight and polydispersity, as well as the variation in composition were monitored with degradation. The changes in thermal and mechanical properties of the specimens were also studied. The results showed that the preferred cleavage of ester bonds resulted in faster degradation in both the hydrolytic and enzymatic cases. Furthermore, the P(TMC-co-CL) had a higher degradation rate in the presence of lipase because it cleaves ester bonds as well as the role of surfactants in the diffusion of the degradation products into water. In vivo, the degradation behavior of the P(TMC-co-CL) depended on their composition—copolymers with a higher TMC content degraded primarily via surface erosion. Bulk degradation was observed for those with a higher CL content. After degradation the mechanical properties and thermal stabilities of the copolymers deteriorated, but the Tm and crystallinity increased via preferred degradation of the amorphous regions. The P(TMC-co-CL) had a tunable degradation rate and remains a promising candidate for clinical subcutaneous implants especially through form-stabilization work.